I can think of an extremely complex and annoying workaround, and though it is less than ideal, it works.

All you need is cron jobs.

What you do:

Assuming ads are turned "on", simply instruct your users to place the advertisement code on your page. It will generate a JavaScript code which will embed the required ad, and will also send a success message to your tht admin panel, which records the success. If after a certain period of time, the ads have not sent a success message, it could suspend the account.

What do you think about that? Its not perfect, but it would work for the most part.